The purpose of the core is to provide expertise in the use of SCID-hu mice and PCR to other basic and clinical researchers. The SCID-hu and PCR cores are administratively combined for historical reasons. The P1 and the core facility technician have significant expertise in the construction of SCID-hu mice and the detection of HIV DNA and RNA in cells and tissues by PCR. The core will provide researchers with SCID-hu mice to be used as an in vivo model of HIV infection and BNX-hu and nude- hu mice to be used in an in vivo model to test HIV vaccines. The construction of SCID-hu mice and BNC-hu mice is a complicated process that requires a breeding colony of SCID and BNX mice, a source of fetal tissue and the surgical expertise required to construct the mice. In addition, following HIV-1 infection of the SCID-hu or BNX-hu mice, they must be contained in a BSL-3 containment facility. These resources are outside the reach of individual researchers and therefore are best provided as a core facility. The core will also perform diagnosis and quantification of HIV-1 infection by the detection of DNA and RNA PCR which should prove extremely helpful for both clinical and basic researchers. In addition, the core will provide expertise in the assessment of cytokine gene expression which will permit researchers to evaluate the in vivo an in vitro immune response to HIV-1 infection. The presence of a centralized core facility permits these assays to be performed by researchers having a high degree of expertise in this area and in a facility designed to minimize contamination. This results in the high quality control required for reproducible results.